It furthermore relates to a control program stored on a data carrier, a control unit for a static VAR compensator and a static VAR compensator which are designed for implementing such a connection method.
Reactive power compensators—so-called SVC (SVC=static VAR compensator) systems—usually comprise a TCR (TCR=thyristor controlled reactance) and at least one filter circuit. They are used for large consumers that are fed alternating current from an AC voltage network, and serve to compensate the reactive power components of the alternating current.
It is usually possible to connect the static VAR compensator to the AC voltage network (or more generally the operating voltage), and to disconnect it from the network again. Transient disturbances in the operating voltage and/or in the flowing currents can arise when the static VAR compensator is connected. In extreme cases, this can cause another system that is likewise being supplied with the operating voltage to perform an emergency shutdown. This results in production stoppages or other operating interruptions.
To avoid such operating interruptions, in the prior art the static VAR compensator is only connected to the operating voltage when other systems or system components that are also supplied via the operating voltage and whose interruption-free operation must be ensured are not currently in operation. This however not only restricts flexibility when connecting the static VAR compensator to the operating voltage. In practice, implementation of this method is additionally only possible with a great deal of effort.
In polyphase AC voltage networks, it is furthermore known to connect the individual phases of the AC voltage network successively to the static VAR compensator with a defined time offset to the voltage zero of the respective phase. This requires special, costly switching devices however.